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(3) TripleFrom 200 mg of CO, when x molecules are re2.89 × 1o-moles of CO2 are left. xwill be(1) 1020 molecules2) 1010 molecules3) 21 molecules4) 1021 molecules |
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Answer» We have 200 mg of carbon dioxide. The molar mass of carbon dioxide is 44g. That is there are 6.022 × 1023molecule of CO2in 44g of CO2. Thus number of moles of CO2in 44g of CO2= 1 number of moles of CO2in 1g of CO2= 1 / 44 number of moles of CO2in 200 mg or 200 × 10-3g of CO2= (1 × 200 × 10-3) / 44 = 4.545 × 10-3moles We are given that after removing X molecules from 200 mg of CO2, 2.89 X 10-3moles of CO2are left. Therefore, number of moles of CO2removed will be = total number of moles of CO2- number of moles of CO2left = 4.545 × 10-3- 2.89 × 10-3 = 1.655 × 10-3moles of CO2 Thus, 1.655 × 10-3moles of CO2were removed. The number of molecules X can be calculated by simply multiplying this quantity with Avogadro's number. So, number of CO2molecules removed will be = 1.655 X 10-3X 6.022 X 1023 = 9.969X 1020molecules of CO2 ~ 10^20 Hence, option (a) is correct. |
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